The National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing, China.
Mol Cell Proteomics. 2010 Sep;9(9):2019-33. doi: 10.1074/mcp.M110.000349. Epub 2010 Jun 6.
The quality of cotton fiber is determined by its final length and strength, which is a function of primary and secondary cell wall deposition. Using a comparative proteomics approach, we identified 104 proteins from cotton ovules 10 days postanthesis with 93 preferentially accumulated in the wild type and 11 accumulated in the fuzzless-lintless mutant. Bioinformatics analysis indicated that nucleotide sugar metabolism was the most significantly up-regulated biochemical process during fiber elongation. Seven protein spots potentially involved in pectic cell wall polysaccharide biosynthesis were specifically accumulated in wild-type samples at both the protein and transcript levels. Protein and mRNA expression of these genes increased when either ethylene or lignoceric acid (C24:0) was added to the culture medium, suggesting that these compounds may promote fiber elongation by modulating the production of cell wall polymers. Quantitative analysis revealed that fiber primary cell walls contained significantly higher amounts of pectin, whereas more hemicellulose was found in ovule samples. Significant fiber growth was observed when UDP-L-rhamnose, UDP-D-galacturonic acid, or UDP-D-glucuronic acid, all of which were readily incorporated into the pectin fraction of cell wall preparations, was added to the ovule culture medium. The short root hairs of Arabidopsis uer1-1 and gae6-1 mutants were complemented either by genetic transformation of the respective cotton cDNA or by adding a specific pectin precursor to the growth medium. When two pectin precursors, produced by either UDP-4-keto-6-deoxy-D-glucose 3,5-epimerase 4-reductase or by UDP-D-glucose dehydrogenase and UDP-D-glucuronic acid 4-epimerase successively, were used in the chemical complementation assay, wild-type root hair lengths were observed in both cut1 and ein2-5 Arabidopsis seedlings, which showed defects in C24:0 biosynthesis or ethylene signaling, respectively. Our results suggest that ethylene and C24:0 may promote cotton fiber and Arabidopsis root hair growth by activating the pectin biosynthesis network, especially UDP-L-rhamnose and UDP-D-galacturonic acid synthesis.
棉花纤维的质量由其最终长度和强度决定,这是初生壁和次生壁沉积的功能。我们使用比较蛋白质组学方法,从 10 天开花后棉花胚珠中鉴定到 104 种蛋白质,其中 93 种在野生型中优先积累,11 种在无绒无毛突变体中积累。生物信息学分析表明,核苷酸糖代谢是纤维伸长过程中上调最显著的生化过程。在蛋白质和转录水平上,有 7 个可能参与果胶细胞壁多糖生物合成的蛋白质斑点在野生型样品中特异性积累。当向培养基中添加乙烯或木质酸(C24:0)时,这些基因的蛋白质和 mRNA 表达增加,这表明这些化合物可能通过调节细胞壁聚合物的产生来促进纤维伸长。定量分析表明,纤维初生细胞壁含有显著较高量的果胶,而在胚珠样品中发现更多的半纤维素。当向胚珠培养基中添加 UDP-L-鼠李糖、UDP-D-半乳糖醛酸或 UDP-D-葡萄糖醛酸时,观察到纤维的显著生长,这些物质都很容易被掺入细胞壁制剂的果胶部分。拟南芥 uer1-1 和 gae6-1 突变体的短根毛通过分别转化相应的棉花 cDNA 或向生长培养基中添加特定的果胶前体来互补。当使用 UDP-4-酮-6-去氧-D-葡萄糖 3,5-差向异构酶 4-还原酶或 UDP-D-葡萄糖脱氢酶和 UDP-D-葡萄糖醛酸 4-差向异构酶产生的两种果胶前体进行化学互补测定时,在分别在 C24:0 生物合成或乙烯信号转导有缺陷的 cut1 和 ein2-5 拟南芥幼苗中观察到野生型根毛长度,表明乙烯和 C24:0 可能通过激活果胶生物合成网络,特别是 UDP-L-鼠李糖和 UDP-D-半乳糖醛酸的合成,来促进棉花纤维和拟南芥根毛的生长。